Its author, Patrick Stuart, recently published a book called Veins of the Earth, illustrated by the sublime Scrap Princess. I've long been a fan of both, but they've really outdone themselves with this book. It's essentially a sourcebook for Underdark adventuring. It assumes Lamentations of the Flame Princess as its system but this is probably the least important part of it.

The 375-page book is consistently astonishing in its sheer evocative power, its strangeness. It restores a sense of true horror and wonder to the often stale Underdark trek. About half the book is a bunch of monsters - absolutely fantastic, bizarre, excellent monsters - and the other half consists of tables, cavern-generation methods, and other tools to help DMs run spelunking adventures. Some examples of things in this book:

- Atomic bees- Something called a "calinated cancer bear"- Something called a "tachyon troll"- Bacteria-people, the Archeans - "a face like a flame-top, an oil-slick halo of metallic fumes" - a primordial elder civilization- An alkaline lion-horror with spores for a mane and corrosive claws that smells "like a bitter sea, or drought-struck lands"- The city-sized monstrosity known as the Civilopede, gathering artworks from broken cities, curated by the parasite-critics on its back- Insane mothman monster-hunters- Zombie coral- Silicon lifeforms who wear elaborate exo-suits to explore beyond their home in the planet's heart- Elaborate rules for cannibalism, starvation, cave-madness- Detailed systems for climbing- Alternative initiative rules involving light sources and lanterns- Extensive advice on cave system generation- 100 cave encounter ideas- 100 lovingly described caves with descriptions like this:

Veins of the Earth

22. FOSSILIZED HIVE

Men, or natural forces, have smashed through empty stone hexagonal cells. An ancient hive of dog-sized wasps. Walls and roof and floor still show the steady grid of larval beds. Some closed caps conceal amberised grubs. The floor is crunchythick with stone mandible fragments, translucent limestone tracery wings and blunted stings.

The above list is a small sample.

The art is plentiful, surreal, impressionistic, messy, and incredibly good, at least to me. There's no effort at photorealism here, but there is demented, frenetic energy and oddity.

It's one of the finest books to come out of the DIY D&D scene, in my opinion.

EDIT: A good review, comparing it to some Wizards books on the Underdark.

Do you think this will ever come out in Print Form, because now I need to get my hands on this wondrous resource. I would have ordered it by now if it had a paperback version. I don't like buying PDF's for some reason.

Yeah, there's a physical copy already available, and I'm sure it's gorgeous, but it's also a massive, ornately illustrated book being shipped from Finland so my understanding is that it costs an arm and a leg. The book alone is $70 USD and I believe that is before shipping.